package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }


    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true) {
                //1.获取队列中订单信息
                try {
                    // 获取消息队列中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    if (list == null || list.isEmpty()) {
                        // 获取失败
                        continue;
                    }
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 获取成功
                    createVoucherOrder(voucherOrder);
                    // ACK确认
                    stringRedisTemplate.opsForStream().acknowledge("stream.orders", "g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }
        private void handlePendingList() {
            while (true) {
                //1.获取队列中订单信息
                try {
                    // 获取消息队列中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create("stream.orders", ReadOffset.from("0"))
                    );
                    if (list == null || list.isEmpty()) {
                        // 获取失败,说明pending-list没有异常消息，结束循环
                        break;
                    }
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 获取成功
                    createVoucherOrder(voucherOrder);
                    // ACK确认
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                }
            }
        }
    }

    private void createVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        // 创建锁对象
        RLock redisLock = redissonClient.getLock("lock:order:" + userId);
        // 尝试获取锁
        boolean isLock = redisLock.tryLock();
        // 判断
        if (!isLock) {
            // 获取锁失败，直接返回失败或者重试
            log.error("不允许重复下单！");
            return;
        }

        try {
            // 5.1.查询订单
            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
            // 5.2.判断是否存在
            if (count > 0) {
                // 用户已经购买过了
                log.error("不允许重复下单！");
                return;
            }

            // 6.扣减库存
            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1") // set stock = stock - 1
                    .eq("voucher_id", voucherId).gt("stock", 0) // where id = ? and stock > 0
                    .update();
            if (!success) {
                // 扣减失败
                log.error("库存不足！");
                return;
            }

            // 7.创建订单
            save(voucherOrder);
        } finally {
            // 释放锁
            redisLock.unlock();
        }
    }
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//    private class VoucherOrderHandler implements Runnable{
//        @Override
//        public void run() {
//            while (true) {
//                //1.获取队列中订单信息
//                try {
//                    // 获取队列中的订单信息
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    // 创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常", e);
//                }
//            }
//        }
//    }
//    private void handleVoucherOrder(VoucherOrder voucherOrder) {
//        //获取用户
//        Long userId = voucherOrder.getUserId();
//        //创建锁对象
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁
//        boolean isLock = lock.tryLock();
//
//        if(!isLock) {
//            log.error("不允许重复下单");
//            return;
//        }
//        try {
//            //获取代理对象
//           proxy.createVoucherOrder(voucherOrder);
//        } finally {
//            lock.unlock();
//        }
//    }
//    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        // 获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行Lua脚本吧
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),    //没有key
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        int flag = result.intValue();
        //2.判断结果是否为0
        if (flag != 0) {
            //3.不为0，代表没有购买资格
            return Result.fail(flag == 1 ? "库存不足！" : "不能重复下单！");
        }
        //获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //5.返回订单id
        return Result.ok(orderId);
    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        Long userId = UserHolder.getUser().getId();
//        //1.执行Lua脚本吧
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),    //没有key
//                voucherId.toString(), userId.toString()
//        );
//        int flag = result.intValue();
//        //2.判断结果是否为0
//        if (flag != 0) {
//            //3.不为0，代表没有购买资格
//            return Result.fail(flag == 1 ? "库存不足！" : "不能重复下单！");
//        }
//        //4.为0，有购买资格，把下单信息保存到阻塞队列
//        //4.1.创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        //4.2.订单ID
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        voucherOrder.setUserId(userId);
//        voucherOrder.setVoucherId(voucherId);
//        //4.3.放入阻塞队列
//        orderTasks.add(voucherOrder);
//        //获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//        //5.返回订单id
//        return Result.ok(0);
//    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //1.查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始！");
//        }
//        //3.判断秒杀是否结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束！");
//        }
//        //4.判断库存是否充足
//        if (voucher.getStock() < 1) {
//            return Result.fail("库存不足！");
//        }
//
//        return createVoucherOrder(voucherId);
//
////        synchronized (userId){
////            // 获取与代理对象（事务）
////            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
////            return proxy.createVoucherOrder(voucherId, voucher);
////        }
//    }

}

//    @Transactional
//    public Result createVoucherOrder(VoucherOrder voucherOrder) {
//        //4.一人一单
//        Long userId = UserHolder.getUser().getId();
//        // 创建锁对象
//        RLock redisLock = redissonClient.getLock("lock:order:" + userId);
//        // 尝试获取锁
//        boolean isLock = redisLock.tryLock();
//        // 判断
//        if (!isLock) {
//            // 获取失败，报错
//            return Result.fail("不允许重复下单");
//        }
//
//        try {
//            //4.1.查询订单
//            int count = query().eq("user_id",userId).eq("voucher_id", voucherOrder).count();
//            //4.2.判断是否存在
//            if (count > 0) {
//                return Result.fail("用户已经购买过一次！");
//            }
//            //6.扣减库存
//            boolean success = seckillVoucherService.update()
//                    .setSql("stock = stock - 1")
//                    .eq("voucher_id", voucherOrder).gt("stock",0)
//                    .update();
//            if(!success) {
//                return Result.fail("库存不足！");
//            }
//            //7.创建订单
//            VoucherOrder voucherOrder = new VoucherOrder();
//            //7.1.订单ID
//            long orderId = redisIdWorker.nextId("order");
//            voucherOrder.setId(orderId);
//
//            voucherOrder.setUserId(userId);
//
//            voucherOrder.setVoucherId(voucherOrder);
//            save(voucherOrder);
//
//            return Result.ok(orderId);
//        } finally {
//            redisLock.unlock();
//        }

